The size of off-highway trucks has increased substantially over the last decade, bringing about a radical change in truck maintenance practices and procedures. As a result, surface mine maintenance mechanics today are faced with the increased hazards of working with larger and heavier tools and components and doing repairs at greater heights, thereby exposing them to a higher potential for serious injury or death. Not surprisingly, the number of accidents involving truck maintenance mechanics is significantly increasing. The Bureau of Mines has assessed the haulage truck maintenance safety problem, analyzing maintenance-accident data over the period 1978-84 in terms of personnel, job activities, truck components and systems, tools involved, and truck design. This assessment, based on the review and interpretation of 1,225 haulage truck maintenance accident reports, identified major factors contributing to these accidents. Overall, young inexperienced workers are involved in most accidents. A typical maintenance accident involves a male mechanic under 33 yr old, with less than 5 yr job experience.